In New Hampshire and Arizona, men openly packing guns came to an event where the president was speaking. In Arizona, one man brandished an assault rifle, a rifle designed for only one thing: killing human beings. Now, it turns out, the men packing the guns at the president’s speech to the Veterans of Foreign Wars in Phoenix, Ariz., were responding to calls by a right-wing radio host who sought to organize people with guns near the president to make a political point.

No one should take this lightly. As reported on the “Rachel Maddow Show,” the radio host — who packed a pistol himself to the Phoenix event — once helped with public relations for a group that was formed to defend a violent militia group known as the Vipers. Twelve members of the Viper Militia, opposed to what they called the “New World Order,” were charged in 1996 with plotting to blow up at least seven government buildings.

This isn’t just harmless macho posturing. What we are witnessing is a dangerous and toxic mixture of hate groups and laws that allow them to carry guns, even to a presidential event.

Any public figure — athlete, celebrity, CEO, politician — accepts the risks that come with appearing in public. Presidents, inevitably the center of controversy and often the fixation of the unbalanced, are particularly at risk. Our Secret Service is professional and skilled, but they understand how hard it is to stop someone packing a gun on a rope line.

There is simply no defense against assault weapons.

Too often, the Secret Service is helpless in the face of AK-47s, M-16s, Uzis, and other assault weapons. The president is left defenseless — as are any other officials at town-hall meetings.

With these weapons, defense is a pretense.

We are headed to an unspeakable horror. It is time to step back from the brink before it is too late. The society must draw sensible lines. Every responsible public official and media commentator should add their voice to condemn those who suggest violence — directly or symbolically — toward those they disagree with. People such as the radio hosts who urge listeners to bring guns to a presidential event should be rebuked, not condoned. Laws enabling the whole Wild West fantasy of packing guns publicly should be repealed, but at the very least we need a national law that makes it illegal to bring guns to events featuring public officials.

The haters, the paranoid, the wingnuts have made their presence known. Now it is up to the rest of us to make it clear that bringing guns to a presidential town hall is simply and unequivocally unacceptable. We’ve seen a doctor murdered in Kansas, a guard shot down at the Holocaust Museum, and, as the Department of Homeland Security warns, the extremes are once more on the rise. We need to hear from the responsible voices and the responsible leaders now — not after the next tragedy.

The Rev. Jesse Jackson is a political activist and the president and founder of the Rainbow/PUSH Coalition. A version of this commentary was published by Tribune Media Services on Aug. 24.